Electrolyte for lithium battery and lithium battery comprising same

ABSTRACT

The electrolyte for a lithium battery includes a non-aqueous organic solvent, a lithium salt, and an additive of the following Formula 1:  
                 
         wherein, X is O, S, CR 2  or NR, where here R is H, a halogen, or an alkyl having a carbon number of less than or equal to 8, or neighboring alkyl groups are combined to each other to form a cycle or hetero cycle, 
 
Y 1 , and Y 2  are the same or different from each other and selected from O, S, CR 2 , and NR, where here R is H, a halogen, or an alkyl having a carbon number of less than or equal to 8, or neighboring alkyl groups are combined to each other to form a cycle or hetero cycle, 
   Y 3  is S, CR 2 , or NR, where here R is H, a halogen, or an alkyl having a carbon number of less than or equal to 8, or neighboring alkyl groups are combined to each other to form a cycle or hetero cycle, and    R a  to R d  are the same or different from each other and selected from H, a halogen, an alkoxy group having a carbon number of less than or equal to 8, or an unsaturated or saturated alkyl group having a carbon number of less than or equal to 8, neighboring alkyl groups are combined to each other to form a cycle or hetero cycle.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2004-0086597 filed in the Korean Intellectual Property Office on Oct.28, 2004, the content of which is incorporated hereinto by reference.

FIELD OF THE INVENTION

The present invention relates to an electrolyte for a lithium battery,and a lithium battery comprising the same, and more particularly, to anelectrolyte for a lithium battery which inhibits overcharging of thebattery, a method of making the same, and a lithium battery comprisingthe same.

BACKGROUND OF THE INVENTION

The use of portable electronic instruments is increasing as electronicequipment gets smaller and lighter due to developments in high-techelectronic industries.

Studies on lithium secondary batteries are actively being pursued inaccordance with the increased need for a battery having high energydensity for use as a power source in these portable electronicinstruments. Such a lithium secondary battery, having an averagedischarge potential of 3.7V (i.e., a battery having substantially a 4Vaverage discharge potential) is considered to be an essential element inthe digital generation since it is an indispensable energy source forportable digital devices such as cellular telephones, notebookcomputers, camcorders, etc. (i.e., the “3C” devices).

Also, there has been extensive research on batteries with effectivesafety characteristics, such as preventing overcharging.

When a battery is overcharged, an excess of lithium ions is deposited ona positive electrode, and an excess of lithium ions is also insertedinto a negative electrode, making the positive and negative electrodesthermally unstable. An eruptive explosion occurs from decomposition ofthe electrolytic organic solvent, and the thermal runaway that occurscauses serious problems with battery safety.

To overcome the above problems, it has been suggested that an aromaticcompound such as an oxidation-reduction additive agent (“redox shuttle”)be added to the electrolyte. For example, U.S. Pat. No. 5,709,968discloses a non-aqueous lithium ion secondary battery that preventsthermal runaway resulting from an overcharge current by using a benzenecompound such as 2,4-difluoroanisole. U.S. Pat. No. 5,879,834 disclosesa method for improving battery safety by using a small amount of anaromatic compound, such as biphenyl, 3-chlorothiophene, furan, etc.which is electrochemically polymerized to increase the internalresistance of a battery during unusual overvoltage conditions. Suchredox shuttle additives increase the temperature inside the batteryearly due to heat produced by the oxidation-reduction reaction, andclose pores of a separator through quick and uniform fusion of theseparator to inhibit an overcharge reaction. The polymerization reactionof these redox shuttle additives consumes the overcharge current toimprove battery safety.

However, the need for high capacity batteries is increasing, and theseredox shuttle additives cannot provide the high level of safety requiredof such high capacity batteries. Therefore, a need exists for anelectrolyte capable of preventing overcharge and ensuring batterysafety.

SUMMARY OF THE INVENTION

An exemplary embodiment of the present invention provides an electrolytefor a lithium battery capable of improving battery safety.

Another embodiment of the present invention provides a lithium batterywhich includes the above electrolyte.

According to one embodiment of the present invention, an electrolyte fora lithium battery includes a non-aqueous organic solvent, a lithiumsalt, and an additive. The additive is represented by the followingFormula 1:

wherein, X is O, S, CR₂, or NR, where here R is H, a halogen, or analkyl having a carbon number of less than or equal to 8, or neighboringalkyl groups are combined to each other to form a cycle or hetero cycle,

Y₁, and Y₂ are the same or different from each other and selected fromO, S, CR₂, and NR, where here R is H, a halogen, or an alkyl having acarbon number of less than or equal to 8, or neighboring alkyl groupsare combined to each other to form a cycle or hetero cycle,

Y₃ is S, CR₂, or NR, where here R is H, a halogen, or an alkyl having acarbon number of less than or equal to 8, or neighboring alkyl groupsare combined to each other to form a cycle or hetero cycle, and

R_(a) to R_(d) are the same or different from each other and selectedfrom H, a halogen, an alkoxy group having a carbon number of less thanor equal to 8, and an unsaturated or saturated alkyl group having acarbon number of less than or equal to 8, neighboring alkyl groups arecombined to each other to form a cycle or hetero cycle.

According to another embodiment of the present invention, a lithiumbattery is provided that includes the above electrolyte, a positiveelectrode including a positive active material being capable ofintercalating and deintercalating lithium ions, and a negative electrodeincluding an active material selected from the group consisting of amaterial being capable of intercalating/deintercalating lithium ions, alithium metal, a lithium-containing alloy, and a material being capableof forming a lithium-containing compound by reversibly reacting lithium.

BRIEF DESCRIPTION OF THE DRAWING

The accompanying drawing, which is incorporated in and constitutes apart of the specification, illustrates embodiments of the invention, andtogether with the description, serves to explain the principles of theinvention.

FIG. 1 is a cross-sectional view of a non-aqueous lithium battery cell.

DETAILED DESCRIPTION OF THE INVENTION

In the following detailed description, the embodiments of the inventionhave been shown and described, simply by way of illustration of the bestmode contemplated by the inventors of carrying out the invention. Aswill be realized, the invention is capable of modification in variousrespects, all without departing from the invention. Accordingly, thedrawings and description are to be regarded as illustrative in nature,and not restrictive.

A cross-sectional view of a general non-aqueous Li-ion cell is shown inFIG. 1.

The Li-ion cell 1 is fabricated by inserting an electrode assembly 8including a positive electrode 2, a negative electrode 4, and aseparator 6 interposed between the positive and negative electrodes 2and 4, into a battery case 10. An electrolyte 26 is injected into thebattery case 10 and impregnated into the separator 6. The upper part ofthe case 10 is sealed with a cap plate 12 and a sealing gasket 14. Thecap plate 12 has a safety vent 16 to release pressure. A positiveelectrode tab 18 and a negative electrode tab 20 are respectivelyattached on the positive electrode 2 and the negative electrode 4.Insulators 22 and 24 are installed on the side and the lower parts ofthe electrode assembly 8 to prevent a short circuit occurrence in thebattery.

In a lithium battery, the temperature of the battery increases abruptlybecause of overcharging due to incorrect operation or break-down of thebattery, or a short circuit occurrence due to a defect in the batterydesign, so that thermal runaway takes place. During overcharging, anexcessive amount of lithium ions are released from the positiveelectrode and deposited on the surface of the negative electrode torender the positive and negative electrodes unstable. As a result,exothermic reactions, such as pyrolysis of an electrolyte, reactionsbetween the electrolyte and lithium, an oxidation reaction of theelectrolyte on the positive electrode, a reaction between theelectrolyte and oxygen gas that is generated from the pyrolysis of thepositive active material, etc., rapidly increase the temperature insidethe battery to cause thermal runaway, and thus, the generation of fireand smoke.

In order to address the above problems, in the present invention acompound represented by the following Formula 1 is used as anelectrolyte additive to improve battery safety on overcharging:

wherein, X is O, S, CR₂ or NR, where here R is H, a halogen, or an alkylhaving a carbon number of less than or equal to 8, or neighboring alkylgroups are combined to each other to form a cycle or hetero cycle,

Y₁, and Y₂ are the same or different from each other and selected fromO, S, CR₂, and NR, where here R is H, a halogen, or an alkyl having acarbon number of less than or equal to 8, or neighboring alkyl groupsare combined to each other to form a cycle or hetero cycle,

Y₃ is S, CR₂, or NR, where here R is H, a halogen, or an alkyl having acarbon number of less than or equal to 8, or neighboring alkyl groupsare combined to each other to form a cycle or hetero cycle, and

R_(a) to R_(d) are the same or different from each other and selectedfrom an alkoxy group having a carbon number of less than or equal to 8,and preferably from methoxy, H, a halogen, or an unsaturated orsaturated alkyl group having a carbon number of less than or equal to 8,or neighboring alkyl groups are combined to each other to form a cycleor hetero cycle.

According to one embodiment, the R is H, a halogen, or a C, to C₈ alkylgroup, and at least one of R_(a) to R_(d) is a halogen, a C, to C₈ alkylgroup, or a C₁ to C₈ alkoxy group.

One preferred example of the additive compound is represented by thefollowing Formula 2:

wherein, X is the same as in the above Formula 1, and

R_(a) to R_(d) are the same or different from each other and selectedfrom an alkoxy group having a carbon number of less than or equal to 8,and preferably from methoxy, H, a halogen, or an unsaturated orsaturated alkyl group having a carbon number of less than or equal to 8,or neighboring alkyl groups are combined to each other to form a cycleor hetero cycle, and at least one of R_(a) to R_(d) is a halogen. The Xis preferably oxygen (O) and the halogen is preferably fluorine.

Another preferred example of the additive compound is a compoundrepresented by the following Formula 3, where, in the above Formula 1 Xis O, Y₁, Y₂ and Y₃ are CR₂, where here R is R₁ to R₆, R_(a) to R_(d)are the same or different from each other and selected from H, ahalogen, an alkoxy group having a carbon number of less than or equal to8, or an unsaturated or saturated alkyl group having a carbon number ofless than or equal to 8, or neighboring alkyl groups are combined toeach other to form a cycle or hetero cycle:

wherein, R¹ and R² are the same as R in the definition of Y₁, R³ and R⁴are the same as R in the definition of Y₂, R⁵ and R⁶ are the same as Rin the definition of Y₃, and R⁷ to R¹⁰ are the same as R_(a) to R_(d) inthe above Formula 1. That is to say, R⁷ to R¹⁰ are the same or differentfrom each other and selected from an alkoxy group having a carbon numberof less than or equal to 8, and preferably from methoxy, H, a halogen,or an unsaturated or saturated alkyl group having a carbon number ofless than or equal to 8, or neighboring alkyl groups are combined toeach other to form a cycle or hetero cycle.

Another preferred example of the additive compound is a compoundrepresented by the following Formula 4, where, in the above Formula 1, Xis O, and Y₁, Y₂ and Y₃ are CH₂:

wherein, R_(a) to R_(d) are the same or different from each other andselected from an alkoxy group having a carbon number of less than orequal to 8, and preferably from methoxy, H, a halogen, or an unsaturatedor saturated alkyl group having a carbon number of less than or equal to8, or neighboring alkyl groups are combined to each other to form acycle or hetero cycle, and at least one of R_(a) to R_(d) is a halogen.

Another exemplary compound is represented by the following Formula 5.

The compound of the above Formula 5 has high oxidation potential, anddoes not induce ignition and so has good overcharge inhibitingcharacteristics.

The additive compound represented by the above Formula 1 initiatespolymerization at more than about 4.5V to coat an electrode surface andincrease resistance between positive and negative electrodes.Alternatively, the compound performs an oxidation/reduction reaction ata voltage of more than about 4.5V to consume an applied current atovercharge and ensure safety of a lithium battery.

The additive compound of the above Formula 1 may be used in an amount of0.01 to 50 wt %, preferably 0.01 to 30 wt %, more preferably 0.01 to 10wt %, and still more preferably 0.01 to 5 wt % based on the total weightof the electrolyte. When the amount of the compound is less than 0.01 wt%, the electrolyte may be ignited. When it is more than 50 wt %, abattery performance may be deteriorated.

The additive compound is added to a non-aqueous organic solventincluding a lithium salt. The lithium salt acts as a supply source oflithium ions in the battery, making the basic operation of a lithiumbattery possible. The non-aqueous organic solvent plays a role of amedium wherein ions capable of participating in the electrochemicalreaction are mobilized.

The lithium salt is preferably at least one selected from the groupconsisting of LiPF₆, LiBF₄, LiSbF₆, LiAsF₆, LiClO₄, LiCF₃SO₃,Li(CF₃SO₂)₂N, LiC₄F₉SO₃, LiAlO₄, LiAlCl₄,LiN(C_(x)F_(2x+1)SO₂)(C_(y)F_(2y+1)SO₂) (wherein x and y are naturalnumbers), LiCl, LiI, and a mixture thereof.

The concentration of the lithium salt preferably ranges from 0.6 to 2.0M, more preferably 0.7 to 1.6 M. When the concentration of the lithiumsalt is less than 0.6 M, the electrolyte performance deteriorates due toits ionic conductivity and when the concentration of the lithium salt isgreater than 2.0 M, the lithium ion mobility decreases due to anincrease of the electrolyte viscosity.

The non-aqueous organic solvent may include a carbonate, an ester, anether, or a ketone. Examples of carbonates include dimethyl carbonate(DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropylcarbonate (MPC), ethylpropyl carbonate (EPC), methylethyl carbonate(MEC), ethylene carbonate (EC), propylene carbonate (PC), and butylenecarbonate (BC). Examples of esters include n-methyl acetate, n-ethylacetate, n-propyl acetate, etc.

It is preferable to use a mixture of a chain carbonate and a cycliccarbonate. The cyclic carbonate and the chain carbonate are preferablymixed together in a volume ratio of 1:1 to 1:9. When the cycliccarbonate and the chain carbonate are mixed in the volume ratio of 1:1to 1:9, and the mixture is used as an electrolyte, electrolyteperformance may be enhanced.

In addition, the electrolyte of the present invention may furtherinclude mixtures of the carbonate solvents and aromatic hydrocarbonorganic solvents. For the aromatic hydrocarbon organic solvent, asolvent represented by the following Formula 6 may be used. Examples ofaromatic hydrocarbon solvents include benzene, fluorobenzene, toluene,trifluorotoluene, chlorobenzene, and xylene.

wherein, R¹¹ is a halogen or a C₁ to C₁₀ alkyl, and n is an integer of 0to 6.

The carbonate solvents and the aromatic hydrocarbon solvents arepreferably mixed together in a volume ratio of 1:1 to 30:1. When acarbonate solvent and an aromatic hydrocarbon solvent are mixed witheach other in the aforementioned volume ratio, and the mixture is usedas an electrolyte, electrolyte performance may be enhanced.

The present invention provides a lithium battery including the aboveelectrolyte. For a positive active material, a compound being capable ofintercalating/deintercalating lithium (a lithiated intercalationcompound) reversibly is used. For the negative active material, acarbonaceous material being capable of intercalating/deintercalatinglithium, a lithium metal, a lithium-containing alloy, and a carbonaceousmaterial being capable of reversibly forming a lithium-containingcompound by reacting lithium is used.

A lithium battery is prepared by the following process. A negativeelectrode and a positive electrode are fabricated by a conventionalprocess, an insulating resin with a network structure is interposedbetween negative and positive electrodes, and then the whole is wound orstacked to fabricate an electrode assembly. Then, the electrode assemblyis inserted into a battery case followed by sealing. The separator is apolyethylene or polypropylene monolayered separator, apolyethylene/polypropylene double layered separator, apolyethylene/polypropylene/polyethylene three layered separator, or apolypropylene/polyethylene/polypropylene three layered separator. Across-sectional structure of the lithium battery prepared by the aboveprocess is shown in FIG. 1.

The lithium battery includes a non-rechargeable lithium battery or arechargeable lithium battery.

The lithium battery including the electrolyte of the present inventionhas improved overcharge inhibiting properties over a battery including aconventional non-aqueous electrolyte.

The following examples further illustrate the present invention indetail, but are not to be construed to limit the scope thereof.

COMPARATIVE EXAMPLE 1

94 g of LiCoO₂ as a positive active material, 3 g of Super P (acetyleneblack) as a conductive agent, and 3 g of polyvinylidenefluoride (PVdF)as a binder were mixed in N-methyl-2-pyrrolidone (NMP) to prepare apositive slurry. The slurry was coated on an aluminum foil having awidth of 4.9 cm and a thickness of 147 μm, dried, compressed, and thencut into a predetermined size, thus manufacturing a positive electrode.

90 g of mesocarbon fiber (MCF from PETOCA Company) as a negative activematerial and 10 g of PVdF as a binder were mixed to prepare a negativeslurry. The slurry was coated on a copper foil having a width of 5.1 cmand a thickness of 178 μm, dried, and compressed, and then cut into apredetermined size, thus manufacturing a negative electrode.

Between the manufactured positive and negative electrodes a polyethylenefilm separator was interposed, followed by winding the whole tofabricate an electrode assembly. The manufactured electrode assembly wasplaced into a battery case and the electrolyte prepared as above wasinjected into the case under reduced pressure, thus completing thefabrication of the prismatic rechargeable lithium battery cell.

For an electrolyte, 1.3M LiPF₆ dissolved in a mixed solvent of ethylenecarbonate, ethylmethyl carbonate, dimethyl carbonate, and fluorobenzenein a volume ratio of 30:55:5:10 was used.

EXAMPLE 1

A prismatic rechargeable lithium battery cell was prepared according tothe same method as in Comparative Example 1 except that 0.25 g of6-fluoro-chroman having the following Formula 7 for the additive wasadded to 5 g of a solution including 1.3M LiPF₆ dissolved in a mixedsolvent of ethylene carbonate, ethylmethyl carbonate, propylenecarbonate, and fluorobenzene in a volume ratio of 30:55:5:10 to preparean electrolyte, and 2.3 g of the electrolyte was added to the batterycase.

EXAMPLE 2

A prismatic rechargeable lithium battery cell was prepared according tothe same method as in Example 1 except that chroman having the followingFormula 8 was used instead of 6-fluoro-chroman.

Lithium battery cells of Examples 1 and 2 and Comparative Example 1 wereovercharged at 2C to evaluate safety of the battery cells. Overchargewas performed by applying 2A of charge current to a fully dischargedcell for 2.5 hours. Measurement results of the safety of the cellsaccording to Examples 1 and 2 and Comparative Example 1 are shown inTable 1.

Standard discharge capacities and high rate charge characteristics ofthe cells according to Examples 1 and 2 are also shown in Table 1. Thehigh rate charge characteristics were as follows: 2C discharge capacitywas represented as a percentage when 1C discharge capacity is 100%.TABLE 1 high rate charge standard discharge characteristic Ignitioncapacity (2C, %) Comparative Ignition — — Example 1 Example 2 IgnitionLess than 500 mAh Less than 15% Example 1 No ignition More than 850 mAhMore than 90%

As shown in Table 1, the battery cell according to Example 1 has superbexcellent safety characteristics while the 2C capacity characteristicswere not reduced, compared with the cell according to ComparativeExample 1.

EXAMPLE 3

A prismatic rechargeable lithium battery was prepared according to thesame method as in Example 1 except that 2,3-dihydro-benzo[1,4]dioxoxineof the following Formula 9 was used as an additive.

EXAMPLE 4

A prismatic rechargeable lithium battery was prepared according to thesame method as in Example 1 except that6-fluoro-2,3-dihydro-benzo[1,4]dioxoxine of the following Formula 10 wasused as an additive.

The expected oxidation and reduction potentials of the additives used inExamples 1 to 4 are described in Table 2. Overcharge inhibitioncharacteristics of Examples 1 to 4 are also shown in the following Table2. TABLE 2 Oxidation Reduction overcharge potential Potential inhibiting(V) (V) characteristics Example 2 4.22 −0.01 Ignition Example 1 4.310.10 No ignition Example 3 4.14 −0.12 Ignition Example 4 4.20 0.06 Noignition, Low oxidation potential

As shown in Table 2, the oxidation and reduction potentials andovercharge inhibiting characteristics are different from each otherdepending on the kind of additive. The additives of Examples 1 and 4 didnot induce ignition. However, the additive of Example 4 has somewhat lowoxidation potential and is not suitable for a high-capacity battery. Theadditives of Examples 2 and 3 induce ignition and are also not suitablefor a battery.

A lithium battery including an electrolyte of the present inventionshows improved overcharge characteristics over the battery including aconventional non-aqueous electrolyte.

While the present invention has been described in detail with referenceto the preferred embodiments, those skilled in the art will appreciatethat various modifications and substitutions can be made thereto withoutdeparting from the spirit and scope of the present invention as setforth in the appended claims.

1. An electrolyte for a lithium battery, comprising: a non-aqueousorganic solvent; a lithium salt; and an additive having the followingFormula 1:

wherein, X is O, S, CR₂, or NR, where here R is H, a halogen, or analkyl having a carbon number of less than or equal to 8, or neighboringalkyl groups are combined to each other to form a cycle or hetero cycle,Y₁, and Y₂ are the same or different from each other and selected fromO, S, CR₂, and NR, where here R is H, a halogen, or an alkyl having acarbon number of less than or equal to 8, or neighboring alkyl groupsare combined to each other to form a cycle or hetero cycle, Y₃ is S,CR₂, or NR, where here R is H, a halogen, or an alkyl having a carbonnumber of less than or equal to 8, or neighboring alkyl groups arecombined to each other to form a cycle or hetero cycle, and R_(a) toR_(d) are the same or different from each other and selected from H, ahalogen, an alkoxy group having a carbon number of less than or equal to8, and an unsaturated or saturated alkyl group having a carbon number ofless than or equal to 8, or neighboring alkyl groups are combined toeach other to form a cycle or hetero cycle.
 2. The electrolyte of claim1, wherein the R is H, a halogen, or a C₁-C₈ alkyl, at least one ofR_(a) to R_(d) is a halogen, an alkyl, or an alkoxy.
 3. The electrolyteof claim 1, wherein the additive is represented by the following Formula2:

wherein X is O, S, CR₂ or NR, where here R is H, a halogen, or an alkylhaving a carbon number of less than or equal to 8, or neighboring alkylgroups are combined to each other to form a cycle or hetero cycle, R_(a)to R_(d) are the same or different from each other and selected from H,a halogen, an alkoxy group having a carbon number of less than or equalto 8, and an unsaturated or saturated alkyl group having a carbon numberof less than or equal to 8, or neighboring alkyl groups are combined toeach other to form a cycle or hetero cycle, and at least one of R_(a) toR_(d) is a halogen.
 4. The electrolyte of claim 3, wherein the X isoxygen.
 5. The electrolyte of claim 3, wherein the halogen is fluorine.6. The electrolyte of claim 1, wherein the additive is represented bythe following Formula 3:

wherein, R¹ to R⁶ are the same or different from each other and selectedfrom H, a halogen, or an alkyl having a carbon number of less than orequal to 8, or neighboring alkyl groups are combined to each other toform a cycle or hetero cycle, and R⁷ to R¹⁰ are the same or differentfrom each other and selected from H, a halogen, an alkoxy group having acarbon number of less than or equal to 8, and an unsaturated orsaturated alkyl group having a carbon number of less than or equal to 8,or neighboring alkyl groups are combined to each other to form a cycleor hetero cycle.
 7. The electrolyte of claim 1, wherein the additive isrepresented by the following Formula 4:

wherein, R_(a) to R_(d) are the same or different from each other andselected from H, a halogen, an alkoxy group having a carbon number ofless than or equal to 8, and an unsaturated or saturated alkyl grouphaving a carbon number of less than or equal to 8, or neighboring alkylgroups are combined to each other to form a cycle or hetero cycle, andat least one of R_(a) to R_(d) is a halogen.
 8. The electrolyte of claim1, wherein the additive is represented by the following Formula 5:


9. The electrolyte of claim 1, wherein an amount of the additive is 0.01wt % to 50 wt % based on the total weight of electrolyte.
 10. Theelectrolyte of claim 1, wherein the lithium salt is at least oneselected from the group consisting of LiPF₆, LiBF₄, LiSbF₆, LiAsF₆,LiClO₄, LiCF₃SO₃, Li(CF₃SO₂)₂N, LiC₄F₉SO₃, LiAlO₄, LiAlCl₄,LiN(C_(x)F_(2x+1)SO₂)(C_(y)F_(2y+1)SO₂) (where x and y are naturalnumbers), LiCl, and LiI.
 11. The electrolyte of claim 10, wherein aconcentration of the lithium salt is 0.6M to 2.0M.
 12. The electrolyteof claim 1, wherein the non-aqueous organic solvent is at least oneselected from the group consisting of a carbonate, an ester, an ether,and a ketone.
 13. The electrolyte of claim 12, wherein the carbonatescomprise at least one selected from the group consisting of dimethylcarbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC),methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methylethylcarbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC), andbutylene carbonate (BC).
 14. The electrolyte of claim 12, wherein thecarbonate is a mixture of a cyclic carbonate and a linear carbonate. 15.The electrolyte of claim 1, wherein the non-aqueous solvent is a mixtureof a carbonate solvent and an aromatic hydrocarbon solvent.
 16. Theelectrolyte of claim 15, wherein the aromatic hydrocarbon solvent isrepresented by the following Formula 6:

wherein R¹¹ is a halogen or a C₁ to C₁₀ alkyl, and n is an integer of 0to
 6. 17. The electrolyte of claim 16, wherein the aromatic hydrocarbonsolvent comprises at least one selected from the group consisting ofbenzene, fluorobenzene, toluene, trifluorotoluene, chlorobenzene, andxylene.
 18. The electrolyte of claim 16, wherein the aromatichydrocarbon solvent is mixed in a volume ratio of 1:1 to 30:1.
 19. Alithium battery comprising: an electrolyte comprising a non-aqueousorganic solvent, a lithium salt, and an additive of the followingFormula 1; a positive electrode including a positive active materialbeing capable of intercalating and deintercalating lithium ions; and anegative electrode including an active material selected from the groupconsisting of a material being capable of intercalating/deintercalatinglithium ions, a lithium metal, a lithium-containing alloy, and amaterial being capable of forming a lithium-containing compound byreversibly reacting lithium:

wherein, X is O, S, CR₂, or NR, where here R is H, a halogen, or analkyl having a carbon number of less than or equal to 8, or neighboringalkyl groups are combined to each other to form a cycle or hetero cycle,Y₁, and Y₂ are the same or different from each other and selected fromO, S, CR₂, and NR, where here R is H, a halogen, or an alkyl having acarbon number of less than or equal to 8, or neighboring alkyl groupsare combined to each other to form a cycle or hetero cycle, and Y₃ is S,CR₂, or NR, where here R is H, a halogen, or an alkyl having a carbonnumber of less than or equal to 8, or neighboring alkyl groups arecombined to each other to form a cycle or hetero cycle, and R_(a) toR_(d) are the same or different from each other and selected from H, ahalogen, an alkoxy group having a carbon number of less than or equal to8, and an unsaturated or saturated alkyl group having a carbon number ofless than or equal to 8, or neighboring alkyl groups are combined toeach other to form a cycle or hetero cycle.